Tuesday, February 1, 2011

Power Supply!

I was in need of a power supply for electricity for my breadboard projects, and was looking to buy a DC bench power supply. Instead, I found someone on the internets that gave me the idea to build one out of an old computer power supply. Since there are other how-tos on the internet I won't go into a lot of detail. It was a fairly painless process involving dremels and drills and lots and lots of wire nuts. Long story short, using one of any five plugs (I used phono plugs instead of banana plugs because of the low-ish amount of current I expect this supply to be able to produce), I can get DC voltages of 3.3, 5, 12, -5, and -12 volts, and by combining any of these two I can additionally get (positive and negative) 8.5, 15.5, 17, and 24 volts. The -5 and -12 terminals can only source a small amount of current compared to the +3.3, +5, and +12 terminals.

Noteworthy note: I installed a switch that shorts out two pins on what would have been the connector for the motherboard. These pins are what tells the power supply to turn on. However, when the switch is flipped off, power is not immediately removed. Currently I have to physically unplug the 120 from the back with the switch on and let the cooling fan dissipate the stored energy. The likely cause of this is one of the pins that are shorted together (the gray one, the black one is ground) needs to have a pull-up resistor to let the power supply know it's been switched off. This mod is not worth disassembling it though, at least not right now.



Also, thanks to FREE MONEY FROM THE GUBMENT, I can now watch TV fo' free! My roommate moved out and took the satellite dish with him, but luckily I have my 80s-era TV with rabbit ears and a brand new DTV converter box furnished by your (and my) tax dollars.


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